The Australians were rocked by Gardner's positive test on Thursday as they look to start their campaign on the right foot against the holders.
Allrounder Gardner, the reigning Belinda Clark Medalist, is stuck in Christchurch isolating for 10 days while the rest of Meg Lanning's side decamped to Hamilton for Saturday's opener.
"We're obviously feeling for Ash," Lanning said.
"She's going well as far as I've heard.
"It's unfortunate that she's tested positive but as as a side we've tried to move on. That's what you have to do in a tournament like this."
Lanning said selectors hadn't settled on a replacement but the 20-year-old was the first name from her lips when asked who could fill Gardner's boots.
"Annabel Sutherland has been bowling and batting extremely well so she's an option," Lanning said.
"Nic Carey has played some really good innings for Australia, and (bowled) some some good overs as well. We feel like we've got options, we just need to decide what exactly that might look like."
England might not relish a reunion with the Victorian: Sutherland took 4-31 in the last Ashes ODI, named player of the match.
Gardner's absence leaves Australia's with 14 fit players, meaning three will miss selection against England.
Two might be top-order bat Grace Harris and T20 specialist Amanda-Jade Wellington, who didn't play in the Ashes ODIs and haven't excelled in warm-up clashes in New Zealand.
The third to miss out will come down to team balance, pitch conditions, and later in the tournament, fitness and form.
Lanning said player management would be limited to "younger fast bowlers".
"There won't be any rotations going on," Lanning insisted.
"We will be picking the best team that we have available each game."
Whoever Australia settle on, a number of players will be making their World Cup debuts.
And regardless, beaten Ashes rivals England believe Australia are the team to beat in New Zealand.
England pace veteran Anya Shrubsole made comments perhaps designed to ease pressure on their side heading into the opening match.
"They (Australia) have obviously been in the form team in world cricket over the last five years. There's no getting away from the fact that they're favourites," she said.
"In lots of respects, we don't really have anything to lose coming out here tomorrow."
Saturday's match begins at 12noon AEDT, or 2pm local, at Seddon Park in the heart of the Waikato.
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